Research Terms
Mechanical Engineering Aerospace Engineering
This 3D printing support material allows for liquid ink-printed silicone structures to have features as small as 8 microns. Silicone is a highly useful material due to its high thermal stability and resistance to weathering, ozone, moisture, and UV radiation. However, soft silicone remains a challenging material to use in additive manufacturing or 3D printing. The most effective support medium available for 3D printing liquid silicone consists of hydrocarbon-based jammed microgels, but these microgels are difficult to formulate. Additionally, the destabilizing interfacial forces between the silicone ink and the microgels in the support medium can lead to the disintegration of more intricate details on the printed silicone structure over time.
Researchers at the University of Florida have developed a 3D medium that uses droplets of water and glycerol emulsified in silicone oil to support silicone prints with ultra-low interfacial tension. The support medium enables silicone 3D prints with smaller, more intricate features, which have applications for personalized implants, lab-on-a-chip devices, tissue/organ-on-a-chip devices, point-of-care devices, biological machines, and other medical devices.
Emulsion-based support material that facilitates 3D printing silicone structures that have finer details
The support material is a packed inverse emulsion in which emulsion droplets containing a mixture of water and glycerol are the dispersed phase, and silicone oil is the continuous phase. The relative proportions of water and glycerol match how fast light travels through the silicone oil, thus making the material optically clear. The mixture of water, glycerol, and silicone oil can have a wide range of different material properties that are easier to tune than those of hydrocarbon-based microgels. Using silicone oil as the continuous phase creates an environment that has ultra-low interfacial tension with deposited silicone-based inks. This prevents the breakup of small printed features, enabling constructs to have features as small as 8 microns in diameter, which is 10 times finer than previously achieved with hydrocarbon-based microgel support systems.
This automated 3D-cell-culture platform enables industrial-scale manufacturing of high-quality tissue cells. The culture conditions can control cell phenotype, gene expression, and stem-cell differentiation. As tissue engineering and 3D bioprinting technologies improve, current cell manufacturing methods will be unable to meet the high-volume requirements for producing functional living cells used to build tissue constructs and eventually organs. Available 2D cell factories greatly increase productivity, but these have limited cell capacity and require human support that prevents production at an industrial scale. Additionally, the adhesion of cells to tissue culture plastic in 2D vessels and 3D bioreactors alters their phenotype and drives stem cell differentiation, which limits cell quality.
Researchers at the University of Florida have developed an automated 3D-cell-culture manufacturing system for large-scale production of high-quality cells. With this system, the biomanufacturing industry can achieve high-volume production of living cells for applications in drug screening, tissue engineering, and regenerative medicine.
Automated manufacturing system capable of mass-producing high-quality tissue cells
This cell manufacturing system uses packed microgels as a 3D printing media for designing extracellular matrix (ECM) structures that contain cells. The microgels swell in liquid culture media to form a packed granular gel. Using the 3D growth medium, an automatic cell culture-manufacturing loop can print 3D cellular structures and incubate them in a perfusion bioreactor, as well as process and re-print them to expand cell populations. The porous microgel packs facilitate liquid perfusion for exchanging nutrients and waste, which controls cell viability and metabolism. Additionally, the 3D ECM microenvironment preserves cell phenotype, gene expression profiles, and stem-cell pluripotency, making it easier to produce high-quality cells with desired properties.
This hydrogel vaccine implants in patients and can carry molecules that train immune cells to treat specific human diseases, such as cancer and infectious diseases. The vaccine is a type of immunotherapy, treatments focused on activating the immune system against cancer and other diseases. Researchers at the University of Florida have created a biocompatible hydrogel vaccine for immunotherapy that results in robust recruitment of different immune cell subsets and serves as a scaffold for interactions of these cells with an antigen loaded in the vaccine. The immune cells recruited within the hydrogel result in a large immune response against the target antigen. The response occurs throughout the body, including sites such as the brain, traditionally considered immune-privileged sites. This eliminates the cost and difficulty of training immune cells ex vivo associated with other immunotherapy modalities, while promoting immune cell viability, antigen uptake, and migration to provide a more efficient immune vaccine.
Immunotherapy vaccine for various cancers and illnesses that efficiently trains the immune system in vivo
The biocompatible nanocomposite hydrogel allows free passage of immune cells in and out of the gel in-situ. The hydrogel vaccine slowly releases a signaling ligand to recruit dendritic cells, NK cells and T cells into the hydrogel. The hydrogel effectively and non-aggressively introduces the antigen nanoparticle mRNA to the dendritic cells. The dendritic cells then present the antigen to the T cells to stimulate them against the antigen, allowing them to attack and kill the target cells within the body, such as tumor cells.
These 3D-printed extracellular vesicle (EV) droplets enable DNA and RNA sequencing to differentiate extracellular vesicle subpopulations. Extracellular vesicles are nanosized vesicles containing a variety of cargo, including mRNA, proteins, and lipids, that nearly all cell types release. EVs are essential to many physiological processes, such as coagulation, inflammatory response, cell maturation, adaptive immune response, bone calcification, and neural cell communication. They also play fundamental roles during cancer progression, suppressing immune surveillance in the tumor microenvironment and establishing the premetastatic niche. Due to the EVs’ ability to transfer their contents to cells in the body and their stability in the bloodstream, there is broad translational potential for EVs in oncology, such as tumor biomarkers. However, the current single-vesicle analysis uses bulk approaches, creating heterogenous EV samples in vesicle structure, contents, and function. This heterogeneity impedes EV development as a biomarker.
Another issue is current microfluid technologies. These technologies form droplets once a single cell enters a fluidic orifice, creating “drops on demand” containing single cells. Current microfluidic technologies at the nanoscale are carefully controlled and are susceptible to low throughput and clogging. Current systems cannot detect EVs beyond a certain threshold; thus, creating single-cell EV droplets is not feasible.
Researchers at the University of Florida have developed 3D-printed aqueous droplets containing extracellular vesicles (EVs) for sequencing the DNA and RNA of single-cell EVs. DNA/RNA sequencing of an individual EV can identify its nucleic acid contents, including structure, composition, and contents for performing a specific function. By characterizing an EV at a single-vesicle resolution level, EV subpopulations of composition and content are differentiated from a heterogenous sample, closing the gap to EVs’ potential as a biomarker. The global EV market was estimated to be worth $169M in 2023 and is poised to reach $356 M by 2028, growing at a CAGR of 16% from 2023-20281.
DNA and RNA sequencing of individual extracellular vesicles (EVs) via 3D printing the EVs within aqueous droplets, differentiating EV subpopulations
This technology uses a 3D printing apparatus to form an aqueous droplet containing a single extracellular vesicle (EV) and a single DNA-barcoded microbead, enabling DNA/RNA sequencing within each EV. A drop of aqueous solution contains an EV and microbead for performing biochemical reactions. The droplet is 3D printed on a medium via a nozzle connected to a supply of the aqueous solution the droplets are made of. Once on the medium, the biochemical reaction occurs within the droplet, and the droplets are separated or pooled from the medium via centrifugation. The aqueous phase with the droplet contents is then removed from the medium. This technology addresses EV heterogeneity and enables the composition, contents, and function identification of extracellular vesicle subpopulations.
This bioreactor enables the 3D printing and maintenance of living cells via the perfusion of nutrients driven by capillary forces through a standard well plate. 3D cell culture technology has grown rapidly in the past several years with many advantages over 2D cell culture, including allowing researchers and doctors to create bio-realistic microenvironments that are used for bioprinting cells and testing medical treatments. The global 3D cell culture market was estimated at $1.5 billion in 2020 and is predicted to continue growing. Available 3D cell culture systems use polymer scaffolds to allow fluid perfusion, but these systems do not provide access for microscopy and can only maintain viable cells for a few days.
Researchers at the University of Florida have developed a perfusion bioreactor that actively delivers nutrients and removes toxic cellular waste via capillary forces. This perfusion bioreactor allows cells to live longer and enables the testing of cellular responses to specific drug therapies.
This perfusion bioreactor delivers nutrients and removes cellular waste using capillary forces for 3D cell culture and cell printing
This perfusion bioreactor for 3D cell culture and cell printing delivers nutrients to cells and removes cellular waste using capillary forces. Fluid is fed by gravity through a narrow opening or microbeads into a traditional well plate containing a liquid-like 3D cell growth medium. As the fluid rises within the well, it connects with a narrow channel and is drawn via capillary forces into a larger, three-dimensional capillary network.
This 3D bio-printed liver tissue model, which exhibits the functions of a human liver, tests for and predicts the liver toxicity of new drug therapies. Current approaches used in testing the potential liver toxicity in a compound during the drug development process are animal models and in vitro cell cultures. Animal models often fail to predict toxicity in humans, leading to costly clinical development failures, black box warnings, or withdrawal of drugs from the market. In vitro cultures lack the complexity of live tissue necessary for proper function and accurate responses. There is a critical need for technologies capable of predicting the toxicity of compounds while increasing the pace and lowering the costs of drug development.
Researchers at the University of Florida have developed a 3D bio-printed liver tissue model for toxicological investigations. The 3D-printed liver model has a function comparable to a human liver, accurately predicting the toxicity of drug compounds. It can also potentially be used for drug metabolism studies, identifying disease markers, assessing gene therapy vectors, screenings, and more.
Tests and predicts for liver toxicity of compounds found in drug therapies
This 3D bio-printed liver tissue model comprises a mixture of liver, hepatocyte cells, endothelial cells, extracellular matrix material, and a micro gel medium made from liver-specific culture. Growth media, containing either known toxic or potential therapeutic compounds, is infused into the liver tissue model to analyze compound toxicity. It will induce cellular toxicity or, alternatively, repair cells, allowing for analyzation of any changes to the model. This model also shows a stable production of albumin and urea levels and has a gene expression profile of typical human liver cells. Additionally, its enzymatic cell function is 70 to 80 percent of human liver cells.
These charge-neutral microgels allow for 3D cell culture and printing. Bioprinting, or placement of biological samples into 3D support media, models cellular morphology, heterogeneity, and genetic profiles in a more accurate and reproducible fashion than traditional 2D cultures. Available 3D cell culture strategies involve the seeding and adhesion of cells into polymer scaffolds with subsequent perfusion of growth media. However, these systems present several limitations, such as limited cell migration, lack of time-effectiveness and optical access for microscopy, and polymer scaffolds restricting the cell environment. Additionally, cell viability is limited to a few days due to the accumulation of cellular waste, leading to localized cytotoxic environments and cell death. It is necessary to devise 3D growth media that allows for improved perfusion.
Researchers at the University of Florida have developed smooth, spherical charge-neutral microgels suitable for 3D cell culture and printing. They can also be used in perfusion bioreactors. The microgels’ spherical shapes enable easier perfusion of materials and make the microgel more absorbent than currently available options.
Microgel-based medium for 3D cell culture and printing, allowing for easier perfusion of materials than currently available formulations
These microgels consist of charge-neutral particles, enabling 3D cell culture and printing. The development of the microgels involves emulsion polymerization, more specifically, an inverse emulsion reaction, resulting in spherical microparticles comprising cross-linked polymers with superior properties for 3D culture. The microgels are derived from monomers, including poly (ethylene glycol) methyl ether acrylate (PEGa), poly(ethylene glycol) diacrylate (PEGda), or acrylamides, N-alkylacrylamides, N,N-dialkylacrylamides, and (meth)acrylates. Packed spherical microgels create well-defined and large pores spaces, improving permeability by a factor of 10,000 compared to currently available formulations, and allowing for easier perfusion of materials.
This micro-biofabrication system combines computer vision, robotics, micromanipulation tools, and a novel culture medium to enable the creation of optimized 3D cellular structures. A level of exquisite detail exists in the intricate pattern and spatial structure of cells found in developing tissue. Micromanipulation tools allow precise translation and placement of single cells. However, available bioprinting systems cannot employ these tools to build highly intricate multicellular 3D structures in a cell-by-cell manner. They cannot hold the deposited cells in place while building structures without creating misconfigured layers or dispersed single cells. Researchers in many fields need effectively perfect multicellular 3D structures to understand topics like embryonic development, function-form relationships, immune signaling, and drug screening for efficacy and toxicity.
Researchers at the University of Florida have developed a cellular micro-masonry system that enables the microfabrication of highly intricate 3D cell structures. A 3D printing culture medium supports cellular structures as they are built one cell at a time using micromanipulation techniques and real-time imaging.
A bioprinting system that builds perfect 3D structures cell by cell
This cellular micro-masonry system integrates a cell translation system, an imaging system, and a 3D culture medium. The culture medium that supports the 3D construction of cells is a liquid-like solid made from jammed microgels swollen in liquid growth media. Through micromanipulation and cell aspiration performed within this culture medium, the system retrieves dispersed cells one at a time, translates them to the building area, and places them at the desired location in 3D space. The system is mounted on a fast-scanning multi-photon microscope to enable real-time tracking of cells, path corrections, and structural refinements during the building process.
These synthetic hydrogel devices offer optimum mesh size to reduce friction and increase lubricity in tissue engineering applications. Millions of patients suffer the loss or failure of an organ or tissue by accident or disease, and more than 8 million U.S. citizens undergo surgery as part of their treatment at a cost of $400 billion each year. Tissue and organ transplantations are limited by donor shortages, and tissue engineering is one way to overcome those shortages. Researchers at the University of Florida have explored self-mated Gemini hydrogel interfaces that control the mesh size for increased lubrication and minimized friction. The hydrogel Gemini interfaces can provide exceptionally low friction coefficients, allowing for increased lubrication and comfort.
Hydrogel surfaces with optimized mesh size for tissue engineering
The mesh size of hydrogel surfaces controls the elasticity and permeability of hydrogels, contributing greatly to the mechanical and transport properties of synthetic material. Researchers at the University of Florida have investigated the relationship between the mesh size of hydrogels and the friction coefficient to develop hydrogel Gemini interfaces meant to increase lubricity and significantly reduce the friction. The preparation of these hydrogel surfaces utilizes a hydrogel with at least one surface forming a quasi-Gemini interface adjacent to a tissue-mimicking hydrogel.
